Fast Configurable-Cache Tuning With a Unified Second-Level Cache

Tuning a configurable cache subsystem to an application can greatly reduce memory hierarchy energy consumption. Previous tuning methods use a level one configurable cache only, or a second level with separate instruction and data configurable caches. We instead use a commercially-common unified second level cache, a seemingly minor difference that actually expands the configuration space from 500 to about 20 000. We develop additive way tuning for tuning a cache subsystem with this large space, yielding 61% energy savings and 9% performance improvements over a nonconfigurable cache, greatly outperforming an extension of a previous method.